1. Field of the invention
This invention relates to an improvement in a ring for spinning machinery.
2. Description of the prior art
A conventional ring for spinning machinery is manufactured in the following way, namely, low carbon steel is cut in the desired ring shape, is subjected to carburizing as a surface hardening treatment for making the carbon content at the surface 0.8-1.0% and is further subjected to quenching. However, with the increasing severity of producing and spinning conditions in recent years, the conventional ring mentioned above has caused such problems as a lack of abrasion-resistance to the sliding traveller, a shorter service life, etc. Also, rings having a surface subjected to a nitriding treatment and rings with a diffused layer of metal carbide formed at the surface have been used, but rings of these types are low in toughness of surface layer and are easy to peel. Thus, these rings are not satisfactory in terms of service life.
In view of the drawbacks of the conventional rings, the present inventor previously invented a ring for spinning machinery which is made of alloy steel containing Cr 1% and has at least at the surface which makes contact with a traveller a martensite layer containing carbide which is made globular in shape and contains 1.5-3% carbon by carburizing and quenching (Japanese Patent No. 1338741-Patent Application Publication No. 61-3892). However, even the ring for spinning machinery of this type is now unable to cope with high speed continuous spinning operations of more than 13,000 r.p.m. spindle speed as used in recent times.